Aside from double-tapping to wake the screen, you can simply draw on the screen to quickly illuminate it.
To unlock the OPPO A37 (A37fw) screen with gestures, follow these steps:
Step 1: Go to 'Settings' and select 'Gestures & Motion.'

Select 'Gestures & Motion.'
Step 2: Choose 'Gestures when screen is off.'

Select 'Gestures when screen is off.'
Step 3: Opt for 'Add gesture to turn off the screen.'

Select 'Add gesture to turn off the screen.'
Step 4: Choose the drawing style.

Choose the drawing style.
Step 5: Opt for 'Unlock.'

Select 'Unlock.'
Congratulations! You have successfully completed the setup process. Best of luck to all of you.